Electroplater and method

ABSTRACT

A method for rinsing a substrate held by a substrate holder in an electroplater includes positioning at least a first portion of the substrate holder and an electroplating bath in the electroplater relative to one another such that the substrate and the first portion of the substrate holder are removed from the electroplating bath. A retractable shutter in the electroplater is closed to where the closed retractable shutter is located between the first portion of the substrate holder and the electroplating bath as positioned. The substrate is rinsed with a solution wherein the closed retractable shutter prevents substantially all of the solution from entering into the electroplating bath.

TECHNICAL FIELD OF THE INVENTION

[0001] The invention relates generally to manufacturing and more specifically to electroplating.

BACKGROUND OF THE INVENTION

[0002] Electrochemical deposition (“ECD”) is a process commonly used to deposit a layer of a metal on a substrate by electrochemical reaction. Substrates are sometimes rinsed prior to and/or after electroplating.

[0003] Traditionally, a de-ionized (“DI”) water solution (or some other type of solution) is utilized to rinse the substrate either ex-situ (for example, in a spin-rinse drier) or in-situ above the electroplater. Ex-situ rinsing requires more floor space for the separate chamber as well as additional equipment. In-situ rinsing may contaminate or dilute the electroplating bath because the rinsing solution falls into the electroplating bath after wetting the substrate.

[0004] Electroplaters typically contain a substrate holder, which may also become contaminated and can be rinsed either in-situ or ex-situ. In-situ rinsing of the substrate holder is disadvantageous as significant quantities of rinsing solution may dilute the electroplating bath. Therefore, ex-situ cleaning of the substrate holder is typically used. Ex-situ cleaning normally involves a substantial amount of time to remove the substrate holder, disassemble it, clean it, reassemble it, and return it to the electroplater.

SUMMARY OF THE INVENTION

[0005] In accordance with one embodiment of the present invention, a method for rinsing a substrate held by a substrate holder in an electroplater includes positioning at least a first portion of the substrate holder and an electroplating bath in the electroplater relative to one another such that the substrate and the first portion of the substrate holder are removed from the electroplating bath. A retractable shutter in the electroplater is closed to where the closed retractable shutter is located between the first portion of the substrate holder and the electroplating bath as positioned. The substrate is rinsed with a solution wherein the closed retractable shutter prevents substantially all of the solution from entering into the electroplating bath.

[0006] The invention has several important technical advantages. Various embodiments of the invention may have none, one, some or all of these advantages. The invention substantially reduces contamination of and/or dilution of an electroplating bath by a rinsing solution. Floor space for substrate fabrication may be reduced as may the dwell time between rinsing and electroplating. Substrate holders may also be cleaned more easily and quickly and non-aqueous solutions may be used. Other technical advantages of the present invention will be readily apparent to one skilled in the art.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] For a more complete understanding of the present invention and its advantages, reference is now made to the following descriptions, taken in conjunction with the accompanying drawings, in which:

[0008]FIG. 1 is a block diagram of one embodiment of an electroplater constructed in accordance with the present invention;

[0009]FIG. 2 is a block diagram of a second embodiment of an electroplater constructed in accordance with the present invention;

[0010]FIGS. 3a-c illustrate the electroplater of FIG. 1 in operation; and

[0011]FIG. 4 is a flow diagram of an example method for in-situ rinsing in accordance with the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0012]FIG. 1 illustrates an embodiment of an electroplater 10 constructed in accordance with the invention. In this embodiment, electroplater 10 includes a substrate holder 12, a nozzle 16, a retractable shutter 22, an electroplating bath 26, and an anode chamber 30.

[0013] The substrate holder 12 may comprise a substrate susceptor or any substrate support structure capable of being positioned or remaining stationary such that the substrate holder 12 may come in contact with the electroplating bath 26. In other words, substrate holder 12, electroplating bath 26 may both be movable or unmovable without departing from the scope of the invention. In one embodiment of the present invention, the substrate holder 12 includes a power supply capable of passing a current along a conductive surface. The power supply can supply a constant current, a constant voltage, or variable waveforms of current or voltage. The power supply can be located in any position and function in any way that will allow electroplating to occur. The nozzle 16 may be any device capable of dispensing an aqueous or non-aqueous rinsing solution 14. Furthermore, as described in more detail in FIGS. 3a-c, nozzle 16 may be one or more dispensers, each capable of dispensing one or more solutions 14.

[0014] The retractable shutter 22 is coupled to the electroplater 10 and, when closed, substrate holder 12 and electroplating bath 26 should be separated by the closed retractable shutter 22. While the entire substrate holder 12 will normally be separated, embodiments could be constructed where only a portion (such as the portion that directly holds the substrate) is separated. Retractable shutter 22 may include one or more sheets, arms, or other components capable of separating substrate holder 12 and electroplating bath 26. Also, retractable shutter 22 may be able to retract by telescoping, repositioning from a joint coupled to electroplater 10, sliding along an axis, or any other movement capable of positioning it between the substrate holder 12 and the electroplating bath 26, when retractable shutter 22 is closed. In some embodiments, retractable shutter 22 is capable of directing substantially all of the aqueous or non-aqueous solution 14 dispensed from nozzle 16 towards a drain 20. It will be understood that retractable shutter 22 is capable of preventing substantially all of a variety of materials from falling into the electroplating bath 26.

[0015] While the illustrated embodiment illustrates a sloped retractable shutter 22, it does not necessarily need to be sloped. Solution 14 could drain out a hole in retractable shutter 22 through a tube, pipe, or otherwise. Moreover, solution 14 could be removed using a vacuum or otherwise. The present invention contemplates any orientation of the shutter sufficient to prevent substantially all of solution 14 from contaminating electroplating bath 26. It further contemplates any type of disposal of solution 14 and the use of any type of solution 14.

[0016] In this embodiment, drain 20 is coupled to the retractable shutter 22 such that the rinsing solution 14 that falls back onto retractable shutter 22 travels from the retractable shutter 22 through the drain 20 and exits the electroplater 10 or is stored therein for later disposal. In one embodiment, drain 20 is a plurality of cavities that allow the rinsing solution 14 captured by the retractable shutter 22 to be removed from the electroplater 10 while preventing substantially all of rinsing solution 14 from contacting the electroplating bath 26. Drain 20 may include one or more cavities, suction devices, or any other devices capable of removing rinsing solution 14 from electroplater 10.

[0017] The electroplating bath 26 may include sulfuric acid, copper sulfate, chloride ion, complex organic additives, or any other type of or mixture of chemicals. The invention contemplates any type of electroplating solution. Furthermore, the electroplating bath 26 may be stationary or capable of movement such that the electroplating bath 26 will come into contact with the substrate holder 12.

[0018] Rinsing solution 14 may be, for example, de-ionized water, isopropanal alcohol, acetone, H₂SO₄ aqueous solution, H₂SO₄/H₂O₂ aqueous solution, or any other solution. The invention is not limited to any particular rinsing solution 14.

[0019] The invention is not limited to any particular anode chamber 30. In this embodiment, anode chamber 30 includes an anode 32 and a diffuser plate 28. The diffuser plate 28 separates the anode chamber 30 from the rest of the electroplating bath 26 and functions to distribute the flow of the electroplating bath 26. Diffuser plate 28 may be formed as a sheet containing a plurality of apertures for permitting the flow of the electroplating bath 26 therethrough. Alternatively, diffuser plate 28 may be formed as a mesh screen within a frame. Again, the invention is not limited to any particular type of these elements.

[0020] In operation, at least a portion of the substrate holder 12 and the electroplating bath 26 are positioned relative to each other such that the closed retractable shutter 22 is located in between. In this embodiment, retractable shutter 22 includes two semi-conical arms that telescope to a closed position located between the substrate holder 12 and the electroplating bath 26. The invention is not limited to any particular type of retractable shutter 22.

[0021] Once the retractable shutter 22 is closed, the nozzle 16 dispenses the rinsing solution 14 that rinses the substrate holder 12 and/or a substrate 24 of FIG. 2 held thereby. The rinsing may occur prior to electroplating, subsequent to electroplating, or both. The substrate 24 may be rinsed separately from substrate holder 12 either before or after plating or at both times. Substantially all of the rinsing solution 14 falls from the rinsed substrate holder 12 or substrate 24 to the closed retractable shutter 22. In this embodiment, retractable shutter 22 deflects the rinsing solution 14 towards drains 20, which allows the rinsing solution 14 to exit the electroplater 10 without contaminating the electroplating bath 26.

[0022]FIG. 2 illustrates another embodiment of the present invention. In FIG. 2, retractable shutter 22 includes one arm that telescopes to a closed flat position (manually, by mechanical force, or by electromechanical force). The retractable shutter 22 is coupled to the electroplater 10 and, when closed, the retractable shutter 22 is located between at least a portion of the substrate holder 12 and the electroplating bath 26 as positioned. In this embodiment, drains 20 are vacuums that pump out the rinsing solution 14.

[0023] In operation, the substrate holder 12 and the electroplating bath 26 are positioned relative to each other such that the closed retractable shutter 22 is located between at least a portion of the substrate holder 12 (or the entire substrate holder 12) and the electroplating bath 26. Once the retractable shutter 22 is closed, the nozzle 16 dispenses the rinsing solution 14 to rinse the substrate holder 12 and/or the substrate. The rinsing may be a pre-rinse prior to electroplating, a post-rinse subsequent to electroplating or both. Substantially all of the rinsing solution 14 falls from the rinsed substrate holder 12 or substrate onto the closed retractable shutter 22. In this embodiment, drains 20 extract the rinsing solution 14 from electroplater 10 using a suction process. While in these embodiments, gravity causes the solution 14 to fall on retractable shutter 22, this is not required. The invention contemplates any arrangement such that the retractable shutter 22 substantially prevents contamination of electroplating bath 26.

[0024]FIGS. 3a-c illustrate an example of the operation of the electroplater 10 of FIG. 1. In this embodiment of the present invention, a substrate 24 is inserted into the substrate holder 12 through an insertion slot 18. Substrate 24 may be a semiconductor wafer, a compact disc, or any object capable of being electroplated (most commonly, an object with a conductive seed layer capable of serving as a nucleation layer). It will be understood that substrate 24 may be inserted into substrate holder 12 before, during, or after the substrate holder 12 and electroplating bath 26 are relatively positioned so that the closed retractable shutter 22 is located between.

[0025] Referring to FIG. 3a, a second nozzle 16 is capable of dispensing a second rinsing solution 34. The second rinsing solution 34 may be any kind of solution as was the case with rinsing solution 14. It will be understood that the second nozzle 16 may be the same nozzle as first nozzle 16 of FIG. 1 or a different nozzle located separately in electroplater 10. Also, second rinsing solution 34 may be the same as or different from first rinsing solution 14 of FIG. 1. Moreover, the-same nozzle 16 could dispense more than one solution 14/34 either simultaneously or at different times. The invention contemplates any number of nozzles 16 or solutions 14/34.

[0026] In operation, the retractable shutter 22 is closed and the second nozzle 16 dispenses the second rinsing solution 34 that rinses the substrate 24. Substantially all of the second rinsing solution 34 falls from the pre-rinsed substrate 24 to the closed retractable shutter 22. In this embodiment, retractable shutter 22 allows substantially all of the rinsing solution 34 to travel towards drains 20 and exit the electroplater 10 without contaminating the electroplating bath 26.

[0027] Referring now to FIG. 3b, the substrate 24 is submerged in electroplating bath 26 and is electroplated. Once substantially all of the second rinsing solution 34 had exited electroplater 10 through drain 20 in FIG. 3a, retractable shutter 22 was previously opened. In this embodiment, the two arms of the retractable shutter 22 telescope in such a way as to allow substrate holder 12 to pass between the resulting opening 42. Substrate holder 12 is then repositioned to where substrate 24 is submerged in electroplating bath 26. The substrate 24 is then subjected to an electroplating process.

[0028] Referring to FIG. 3c, a third nozzle 16 is capable of dispensing a third rinsing solution 40. The third rinsing solution 40 may be the same or a different solution from the second rinsing solution 34. Also, it will be understood that the third nozzle 16 may be the same nozzle as first nozzle 16 and/or second nozzle 16 or may be a different nozzle located separately in electroplater 10. Also, third rinsing solution 40 may be the same as or different from first rinsing solution 14 and/or second rinsing solution 34.

[0029] In operation, after the substrate is electroplated, the substrate holder 12 and the electroplating bath 26 are positioned such that substrate 24 is no longer in contact with the electroplating bath 26. Then, the retractable shutter 22 is again closed and the third nozzle 16 dispenses the third rinsing solution 40 that rinses the substrate 24. Substantially all of the third rinsing solution 40 falls from the post-rinsed substrate 24 onto the closed retractable shutter 22. In this embodiment, retractable shutter 22 allows substantially all of the third rinsing solution 40 to travel towards drains 20 and exit the electroplater 10 without contaminating the electroplating bath 26.

[0030]FIG. 4 illustrates one method for rinsing a substrate and substrate holder in accordance with the present invention. Some or many of these steps can be omitted without departing from the scope of the invention. In addition, various steps might be repeated with different frequency. For example, a substrate might be rinsed each time but the substrate holder rinsed once for processing of a plurality of substrates. Nothing in the description of FIG. 4 is intended to limit in any way the potential uses of the invention or the options as far as construction. The method begins at step 200 in which the substrate holder 12 and the electroplating bath 26 are relatively positioned to one another such that the retractable shutter 22 is positioned between them when it is closed. As described above, the substrate holder 12 and the electroplating bath 26 may both be capable of movement. While the substrate holder 12 will normally lie above electroplating bath 26 when the shutter is closed, this is not required.

[0031] At step 205, the retractable shutter 22 is closed. Once the retractable shutter 22 is closed, substrate holder 12 and electroplating bath 26 should be separated by the closed retractable shutter 22. Next, at step 210, a first rinsing solution is dispensed to rinse the substrate holder 12. Nothing herein prevents the substrate or substrate holder from being rinsed multiple times by one or more solutions at any given time.

[0032] After the substrate holder 12 is rinsed, the substrate 24 is inserted into substrate holder 12 at step 215. The substrate 24 may be inserted by being dropped, placed by robotic arm, or any other process that results in the substrate 24 being located in the substrate holder 12. Next, at step 220, the second rinsing solution 34 is used to rinse the substrate. It will be understood that the second rinsing solution 34 may be the same as or different from first rinsing solution 14, as noted above.

[0033] During or after the pre-rinsing of the substrate 24, second rinsing solution 34 is drained at step 225. The first rinsing solution 14 can be drained after step 210 or during any step up to step 225. After draining, retractable shutter 22 may be opened at step 230.

[0034] Once the shutter is retracted and opening 42 is large enough for substrate holder 12 to travel through, at step 235 the substrate 24 is submerged into the electroplating bath 26. Once the substrate 24 is submerged, the substrate 24 is electroplated.

[0035] After electroplating, the substrate 24 is extracted from electroplating bath 26. Next, at step 250, the retractable shutter 22 is closed.

[0036] At step 255, a third rinsing solution 40 is dispensed to rinse the substrate 24 after electroplating. As noted above, third rinsing solution 40 may be the same as or different from first rinsing solution 14 and/or second rinsing solution 34. During or after the post-rinsing of the substrate 24 is complete, third rinsing solution 40 is drained from electroplater 10 at step 225.

[0037] Although the present invention has been described in detail, it should be understood that various changes, substitutions and alterations can be made hereto without departing from the sphere and scope of the invention as defined by the appended claims.

[0038] To aid the Patent Office, and any readers of any patent issued on this application in interpreting the claims appended hereto, applicants wish to note that they do not intend any of the appended claims to invoke ¶6 of 35 U.S.C. §112 as it exists on the date of filing hereof unless “means for” or “step for” are used in the particular claim. 

What is claimed is:
 1. A method for rinsing a substrate held by a substrate holder in an electroplater, comprising: positioning at least a first portion of the substrate holder and an electroplating bath in the electroplater relative to one another such that the substrate and the first portion of the substrate holder are removed from the electroplating bath; closing a retractable shutter in the electroplater, wherein the closed retractable shutter is located between the first portion of the substrate holder and the electroplating bath as positioned; and rinsing the substrate with a first solution wherein the closed retractable shutter prevents substantially all of the solution from entering into the electroplating bath.
 2. The method of claim 1, wherein rinsing the substrate with a first solution further comprises pre-rinsing the substrate prior to electroplating.
 3. The method of claim 2 further comprising post-rinsing the substrate with a second solution subsequent to electroplating.
 4. The method of claim 3, wherein the first solution and the second solution comprise the same solution.
 5. The method of claim 3, wherein the first solution and the second solution comprise different solutions.
 6. The method of claim 1, wherein rinsing the substrate with a first solution further comprises post-rinsing the substrate subsequent to electroplating.
 7. The method of claim 1 further comprising drying the rinsed substrate.
 8. The method of claim 1, wherein the substrate comprises a semiconductor device.
 9. A method of cleaning, comprising: positioning at least a first portion of a substrate holder and an electroplating bath in an electroplater relative to one another such that the first portion of the substrate holder is removed from the electroplating bath; closing a retractable shutter in the electroplater, wherein the closed retractable shutter is located between the first portion of the substrate holder and the electroplating bath as positioned; and rinsing the substrate holder with a first solution, wherein the closed retractable shutter prevents substantially all of the solution from entering into the electroplating bath.
 10. The method of claim 9, wherein rinsing the substrate holder further comprises pre-rinsing the substrate holder prior to electroplating.
 11. The method of claim 9, wherein a substrate is held by the substrate holder and the method further comprises pre-rinsing the substrate with a second solution prior to electroplating.
 12. The method of claim 11 further comprising post-rinsing the substrate with a third solution subsequent to electroplating.
 13. The method of claim 12, wherein the first solution, the second solution, and the third solution comprise the same solution.
 14. The method of claim 12, wherein the first solution, the second solution, and the third solution comprise different solutions.
 15. An electroplater, comprising: an electroplating bath; a substrate holder operable to hold a substrate in the electroplating bath during electroplating of the substrate; a first nozzle operable to dispense a first solution; and a retractable shutter in the electroplater, wherein the retractable shutter is operable to be opened or closed, wherein when the retractable shutter is closed, it is located between at least a first portion of the substrate holder and the electroplating bath as positioned.
 16. The electroplater of claim 15 further comprising a spin-rinse dryer operable to dry the substrate holder and the substrate.
 17. The electroplater of claim 15, wherein the first nozzle is operable to pre-rinse the substrate prior to electroplating with the first solution and wherein the system further comprises a second nozzle operable to post-rinse the substrate subsequent to electroplating with a second solution.
 18. The electroplater of claim 15, wherein the first nozzle is operable to dispense the first solution when the retractable shutter is closed.
 19. The electroplater of claim 15, wherein the first nozzle is operable to dispense a second solution different from the first solution.
 20. The electroplater of claim 15, wherein the system further comprises a drain coupled to the retractable shutter, wherein the retractable shutter is operable to deflect substantially all of the first solution to the drain. 